Please join us for this Climate Coffee with Shenjie Zhou on

Slowdown of Antarctic Bottom Water export driven by climatic wind and sea-ice changes

Antarctic Bottom Water (AABW) is pivotal for oceanic heat and carbon sequestrations on multidecadal to millennial timescales. The Weddell Sea contributes nearly a half of global AABW through Weddell Sea Deep Water and denser underlying Weddell Sea Bottom Water that form on the continental shelves via sea-ice production. Here we report an observed 30% reduction of Weddell Sea Bottom Water volume since 1992, with the largest decrease in the densest classes. This is probably driven by a multidecadal reduction in dense-water production over southern continental shelf associated with a >40% decline in the sea-ice formation rate. The ice production decrease is driven by northerly wind trend, related to a phase transition of the Interdecadal Pacific Oscillation since the early 1990s, superposed by Amundsen Sea Low intrinsic variability. These results reveal key influences on exported AABW to the Atlantic abyss and their sensitivity to large-scale, multidecadal climate variability.

Zhou, S., Meijers, A.J.S., Meredith, M.P. et al. Slowdown of Antarctic Bottom Water export driven by climatic wind and sea-ice changes. Nat. Clim. Chang. 13, 701–709 (2023). https://doi.org/10.1038/s41558-023-01695-4

What is a Climate Coffee?

#climatecoffees are short (circa 40 min: 20 min talk + 20 min Q&A), relaxed meetings for scientists to share ideas, discuss methods and communicate new results. They are open to speakers of all levels of seniority, we especially encourage early-career scientists to become a speaker. The Coffees are an exciting opportunity for scientists to build a network and disseminate recent results, peer-to-peer. We invite researchers from across the climate science community to join us for this series of regular online knowledge exchange events.

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It will be sent via Eventbrite to you in due time.

About our speaker

Shenjie Zhou is a postdoctoral physical oceanographer at British Antarctic Survey. Shenjie cares about the ocean’s role in the climate systems. Specifically, the interaction between the ocean, atmosphere and more recently cryosphere under the changing climate.

He obtained his PhD in physical oceanography at University of East Anglia in 2020, on topics of Ocean’s response to the stochastic atmospheric forcing, where he was trained to tackle the questions using numerical modelling technique. Shenjie investigated how the Atlantic Meridional Overturning Circulation and related North Atlantic Circulation including subpolar gyre circulation responds to the misrepresented mesoscale atmospheric variabilities and how these variabilities can possibly shape the circulation behaviours on decadal timescales.

Shenjie carried his interests in the overturning circulation to his postdoctoral research at BAS, where Ihe started working on the deep ocean ventilation in the Weddell Sea, the southern end of the Atlantic Ocean. The deep ocean ventilation engines the abyssal overturning circulation branch residing underneath the AMOC, which is critical for heat and carbon sequestration process. Shenjie worked this question with EU Horizon 2020 SO-CHIC project, and will keep working on it with the Horizon Europe OCEAN:ICE project.

Organisation

The Climate Coffees are organized by the Horizon Europe project OCEAN:ICE, the Danish Meteorological Institute and the European Climate Research Alliance.

Looking forward to seeing you at this Climate Coffee!

Chiara, Erika (OCEAN:ICE/DMI) and Sissi (ECRA)

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